The present invention generally relates to a control pedal assembly for a motor vehicle and, more particularly, to a control pedal assembly for a motor vehicle which is electronically coupled and has a mechanical hysteresis device to simulate the feel of a control pedal assembly which is mechanically coupled.
Control pedals are typically provided in a motor vehicle, such as an automobile, which are foot operated by the driver. Separate control pedals are provided for operating brakes and an engine throttle. When the motor vehicle has a manual transmission, a third control pedal is provided for operating a transmission clutch. The control pedals are typically connected to control devices by cables or other mechanical transmission devices which convert the limited rotary motion of the pedals into useful mechanical motion at the control devices to control operation of the motor vehicle. The engine throttle is typically connected to an accelerator pedal through a mechanical cable such as a Bowden cable. This mechanical linkage has a desirable and functional xe2x80x9cfeelxe2x80x9d wherein the pressure required for advancing the control pedal to accelerate the motor vehicle is greater than the pressure required for maintaining the pedal in a fixed position to maintain the motor vehicle at a constant speed. This difference of required pressures is often referred to as a xe2x80x9chysteresis effectxe2x80x9d. The pressure required to advance the control pedal is typically relatively high. This is desirable to obtain adequate return pressure to return the pedal to the idle position in a desired amount of time when foot pressure is removed from the control pedal. The pressure required to advance the control pedal is easily provided when accelerating but would become uncomfortable over time to maintain a relatively constant speed. Therefore, the hysteresis effect is important in providing a reasonable force for maintaining the accelerator pedal in position to comfortably drive at a generally constant speed while providing an adequate return force for returning the control pedal to idle to decelerate the motor vehicle.
There have been attempts to introduce an electrical linkage between the control pedal and the control device. Typically, a position sensor converts the position of the control pedal into an electrical signal which is sent to the control device. This electrical linkage has far fewer routing limitations than the mechanical linkages. The control pedal, however, must be provided with a hysteresis device to obtain the xe2x80x9cfeelxe2x80x9d of a control pedal having a mechanical linkage. Various proposals have been made to provide a control pedal with both an electrical linkage and a mechanical hysteresis device. While these proposed control pedals may adequately provide the xe2x80x9cfeelxe2x80x9d of a control pedal with a mechanical linkage, they are relatively complex and expensive to produce. Additionally, the proposed control pedals require a relatively large amount of space. Accordingly, there is a need in the art for a control pedal assembly which is electronically coupled and has a mechanical hysteresis device, is relatively simple and inexpensive to produce, and is highly reliable in operation.
The present invention provides a control pedal assembly which overcomes at least some of the above-noted problems of the related art. According to the present invention, a control pedal assembly comprises a support structure, a pedal arm pivotally mounted to the support structure and carrying a pedal on a rearward side of the pedal arm, and a hysteresis device adapted to generate a desired feel in response to pivotal movement of the pedal arm. The hysteresis device is secured to either the support structure or the pedal arm and engages the other. The hysteresis device is located below a pivot axis of the pedal arm and is located at a forward side of the pedal arm opposite the pedal. Locating the hysteresis device in this manner reduces the packaging size of the pedal assembly.
According to another aspect of the present invention, a control pedal assembly comprises a support structure, a pedal arm pivotally mounted to the support structure and carrying a pedal, and a hysteresis device adapted to generate a desired feel in response to pivotal movement of the pedal arm. The hysteresis device includes a plunger movable within a chamber between an extended position and a depressed position upon rotation of the pedal arm and at least one spring member resiliently biasing the plunger to the extended position. Such a hysteresis device is relatively simple and inexpensive to produce and is highly reliable in operation.
According to yet another aspect of the present invention, a control pedal assembly comprises a support structure, a pedal arm pivotally mounted to the support structure and carrying a pedal, and a hysteresis device secured to the support structure. The hysteresis device comprises a plunger engaging the pedal arm and movable within a chamber between an extended position and a depressed position upon rotation of the pedal arm and at least one compression spring resiliently biasing the plunger to the extended position. The chamber forms a first friction surface and the plunger has a plurality of prongs forming a second friction surface engagable with the first friction surface to resist pivotal movement of the pedal arm. The prongs form angled surfaces engaging the spring to wedge the prongs in an outward direction to engage the first and second friction surfaces with increasing force upon compression of the spring.
From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of control pedal assemblies. Particularly significant in this regard is the potential the invention affords for providing a high quality, feature-rich, low cost assembly. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.